1. Field of the Invention
This invention relates to a motor magnet fixing device, particularly to one provided with two press rings and a plurality of locking members to have motor magnets clamped firmly between the two press rings, able to fix the motor magnets in position and facilitate its assembly.
2. Description of the Prior Art
Generally, a conventional motor magnet fixing device is provided with plural magnets preset in number to be equidistantly secured on the inner wall of a motor housing by means of adhesives, and a rotor installed in the interior of the motor housing to be actuated to rotate and produce electric force by change of the magnetic line of force and the magnetic field of the magnets. However, the adhesives may become weakened in its viscosity after used for a long period of time, rendering the magnets likely to fall off and causing damage to the motor. In addition, when glued on the inner wall of the motor housing, the magnets, due to mutual attraction and repelling of magnetic polarity, are likely to move bias and hard to be precisely fixed in position. As a result, it is inconvenient to assemble the magnets and impossible to separate and arrange the magnets equidistantly with precise intervals, thus failing to make magnetic action of the magnets distributed evenly and unable let the motor operate stably.
Another conventional motor magnet fixing device devised by the inventor of this invention, as shown in FIG. 1, includes a motor housing 10, plural magnets 11 preset in number, two positioning rings 12 and plural bolts 13 combined together. The motor housing 10 is a long cylindrical hollow one, and the magnets 11 are respectively shaped as a long arcuate plate matching with the curvature of the inner wall of the motor housing 10 so that the magnets 11 can directly be fixed on the inner wall of the motor housing 10 by their attractive force. The two positioning rings 12 have their circumferential edges respectively bent inward to form a protruding rim 121 for engaging and positioning the opposite ends of the magnets 11 and their annular surfaces respectively bored with four insert holes 122 spaced apart equidistantly. Each insert hole 122 of the two positioning rings 12 has its opposite sides respectively extending downward to form a projecting edge 123 for engaging part of the end corners of the magnet 11. The bolts 13 are respectively inserted through the insert holes 122 of the two opposite positioning rings 12 and locked with a nut 131, letting the magnets 11 firmly fixed inside the motor housing 10 by the two positioning rings 12.
However, due to the attracting and repelling action of magnetic polarity, when the magnets 11 are assembled on the opposite inner walls of the motor housing 10 by means of the two positioning rings 12, it will always cause trouble in operation, and when the bolts 13 are respectively inserted through the insert hole 122 and the gaps between two magnets 11 and locked with the nut 131, the bolts 13 will be actuated to sway bias by the magnetic action of the magnets 11 and hard to be fixed in position quickly and precisely, resulting in difficulty and inconvenience in assembly and operation.